On 26 August 2013, Cunliffe announced a second leadership bid after David Shearer's departure from the leadership and was elected on 15 September 2013. Following Labour's defeat at the general election in September 2014, he resigned as leader of the Labour Party.[3]

In the 2002–2005 Parliament he held the ICT portfolios and was Associate Minister of Finance and Revenue, after previously serving as Parliamentary Private Secretary for Finance and Commerce.

During his first term (1999–2002) he served as Chair of the Commerce Select Committee, and sat on the Finance and Expenditure and Regulations Review select committees.

In 2006, in his previous role as Immigration Minister, he announced a major review of the Immigration Act 1987.[9] As Minister for Communications and Information Technology he announced extensive pro-competitive reform of the telcommunications sector, including local loop unbundling and operational separation of then Telecom New Zealand.[10]

In May 2006 Cunliffe was referred to the Securities Commission by the NZX for commenting on Telecom's future dividend plans,[11] causing Telecom's stock price to drop. The Securities Commission found that no law had been breached and no action was taken.[12]

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In February 2008, as the Minister of Health, Cunliffe dismissed the Hawke's BayDistrict Health Board over political, monetary and conflict of interest troubles.[15]Napier Mayor Barbara Arnott and a number of members of the district voiced opposition to Cunliffe's move as many of the board members were democratically elected.[16] Following the release of a Health Ministry-commissioned independent report into the matter, Cunliffe referred to the board as "nasty little nest of self-perpetuating provincial elites".[17]

After the 2008 general election defeat of the Labour Party, Cunliffe was made Labour's spokesman for Finance, shadowing National's Finance Minister, Bill English. Cunliffe had been touted as a future leader of the party, and party insiders had suggested he seriously considered challenging Phil Goff as leader in the aftermath of the 2008 election. Speculation of a leadership challenge again arose during the June 2010 expenses scandal and again after the "Cartergate" affair.

In November 2012 during a Labour Party conference, there was much media speculation Cunliffe would launch a challenge against David Shearer for leadership of the party.[19] On the morning of 19 November, Cunliffe confirmed he was not challenging Shearer, and would indeed back him if a vote was taken.[20] Labour Chief Whip Chris Hipkins publicly refuted that Cunliffe had not been making a bid for the leadership over the conference weekend, and stated that fellow caucus members were frustrated with Cunliffe's behaviour.[21]

On 20 November 2012, Shearer sacked Cunliffe as economic development spokesman, and demoted him to the back bench, citing Cunliffe's inability to express his support for Shearer's leadership at the Labour Party Conference. Cunliffe denied that he had been disloyal. Cunliffe was left with no spokesmanships.[22] In February 2013 Shearer reshuffled his caucus lineup. Cunliffe was given the Revenue portfolio, but was not promoted back into the shadow cabinet.[23]

On 22 August 2013, Shearer announced his resignation as leader of the Labour Party, fuelling speculation that Cunliffe would make another bid for the leadership. Cunliffe did not confirm his candidacy immediately, saying to the press in Parliament that same day: "I am going to be taking the next few days to consult with my family, with colleagues and with party supporters and I won't be making a decision until after I have done that."[24] Victoria University of Wellington's iPredict online predictions market showed the probability of Cunliffe becoming the next leader of the Labour Party at 66%, compared to under 26% support for Shearer's deputy Grant Robertson, social development spokesperson Jacinda Ardern was at 5%, and list MP and former union leader Andrew Little was on 2%.[25]

Cunliffe formally entered the 2013 New Zealand Labour Party leadership election during a press conference in his New Lynn electorate office, saying he had consulted colleagues, supporters, and family and had been "humbled by the response."[26] He also said they had expressed confidence in his ability to "bring together a party and a government that provides a strong, clear voice for fairness, inclusion, and prosperity to be shared by all."[27] His announcement came in the wake of a ONE News Colmar Brunton poll released by the current affair program Q+A which showed Cunliffe winning the support of 29% of the eligible voters asked, and 32% of those polled who support Labour. Challengers Shane Jones and Grant Robertson are on 11% and 10%, respectively.[28] After the first public Labour Party leadership selection process in New Zealand history, Cunliffe was elected leader on 15 September 2013.[29] He won with the support of 32% of the Labour Party caucus, 60% of Labour Party members, and 70% of affiliated unions.[30]

This section needs expansion. You can help by adding to it.(September 2016)

Cunliffe speaking in October 2013

Cunliffe was perceived as widely disliked by his colleagues in the Labour Party caucus. In the leadership contest he won first-preference votes from only one-third of Labour MPs.[31] His leadership of the party was marked by continued infighting and instability.

Labour performed poorly in the public opinion polls throughout Cunliffe's tenure as leader. Political commentator John Armstrong criticised "the lack of 'fresh policy' coming out of Labour" and lamented there was "a lack of urgency, which is failing to provide the momentum to keep Labour in the headlines".[33]

Labour launched its campaign for 2014 New Zealand general election in Auckland on 21 July. Cunliffe announced several flagship election policies, including a promise of free GP visits and prescriptions to pregnant women and those aged under 13 and over 65.[34] In a speech he stated, "We are basing our policies on a very old idea. That your healthcare is based on your health need, not on the size of your wallet."[34]

Cunliffe's performance in the leadership debates was viewed as mixed. Cunliffe was judged to have performed poorly in the 2 September The Press leaders' debate. Key claimed a win after Cunliffe could not answer whether family homes held in a trust would be exempt under Labour's capital gains tax policy.[35]

In August, the Labour Party's position in the opinion polls dropped to 22.4%, with Cunliffe registered 11% support as preferred Prime Minister.[36]

During the election campaign, Cunliffe met the alleged offender in the Queenstown suppressed indecency case. He said he had arranged for the person to meet a Labour candidate but that he had no idea about the person's controversial background and that had he known, no such meeting would have taken place.[37]

Cunliffe led the party to its worst general election result since 1922.[38] The National Party returned to power with 48.1% of the vote (its best result since 1951) while Labour claimed just 24.7%.[38] Cunliffe initially vowed to remain as the party leadership, despite the poor election result. On 27 September Cunliffe formally resigned as leader but announced he was re-contesting in the 2014 leadership election.[36] Later on 13 October, following widespread criticism, he announced he was pulling out of the leadership race.[36]

Cunliffe is a supporter of a New Zealand republic. During the Address-In-Reply debate on 4 September 2002, Cunliffe said: "A New Zealand where we journey together towards maturity as a nation, and to the Commonwealth republic I personally believe we will become before the Treaty turns 200".[40]

Cunliffe married prominent Auckland lawyer Karen Price when he was 21 and she was 19. They had two sons, and lived in the Auckland suburb of Herne Bay.[6] They separated in 2015.[1] Cunliffe's father Bill was born in Ngahere in 1915 and worked at the railways. His great-grandfather, William Cunliffe, married Phoebe Seddon, the elder sister of Richard Seddon, who would later become known as 'King Dick'. Seddon, New Zealand's longest serving prime minister, was thus Cunliffe's great-(great-)uncle.[41]

Cunliffe is the son of an Anglican minister, and was raised in the Church of England. He has described himself as a "liberal Anglican," and an "infrequent attender of church, but it's a big part of my life."[42] He attends St Matthew's Anglican Church in Auckland, and is a supporter of the Auckland City Mission.